On a recent Saturday, state Department of Transportation personnel and work crews showed Mahnkey around the pit that will become the south end of the tunnel — “the belly of the beast,” as he put it.

The actual drilling hasn’t yet begun — it’s scheduled to start sometime this summer. But Bertha is in place and ready to rumble, he said.

“This is truly a big machine, way over 100 yards long, including all the trailing stuff,” Mahnkey said. “I thought I was in the shaft gallery on the Queen Mary in Long Beach.”

The drilling device is the largest in the world, according to the transportation department. It’s more than 57 feet in diameter — roughly as tall as a five-story building.

Bertha was shipped to Seattle in parts following its construction in Osaka, Japan. The machine arrived in Elliott Bay in April and was reassembled in an 80-foot-deep pit to the west of Safeco and CenturyLink fields.

Crews spent about an hour showing Mahnkey around, he said. He was told four people will be working 10-hour shifts on the project five days a week.

As the dirt is dug out, another machine will divert it to a conveyor belt which will take it back out of the tunnel to the south, he said.

The tunneling is expected to take 14 months and the four-lane toll tunnel is scheduled to open to traffic in early 2016. The project cost is $3.1 billion.

Junelle Erickson of Everett writes: Regarding the repaving of southbound Highway 99 in Lynnwood after the recent water and electric systems upgrades, I’m wondering if there is a possibility that the repaving could be extended south to 148th Street SW.

As you drive under the Highway 525 overpass and proceed south, the highway has been patched so often that it is hard to see the lane dividers. These patches and the faded lane markers make it extremely difficult, especially in the rain or at night, to discern the lane parameters.

Travis Phelps, a spokesman for the state Department of Transportation, responds: The state can’t require utilities to pave beyond the area they’re affecting during construction. The transportation department assesses the pavement along each highway every two years. This section of Highway 99 will be inspected sometime this summer. If this section of the highway must be repaved, it will occur sometime between 2015 and 2017.

If the inspection finds sections of highway that must be repaved immediately, the transportation department will rely on its maintenance crews to conduct interim spot repairs until funding can be secured for a permanent fix.

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